1. Field of the Invention
The present invention relates to an aqueous ink for an inkjet.
2. Description of the Related Art
An inkjet recording system is a printing system in which printing is conducted by spraying a liquid ink with a high degree of fluidity from a very fine nozzle and adhering the ink onto a recording medium such as a sheet of paper. This system enables the printing of high-resolution, high-quality images at high speed and with minimal noise, using a comparatively inexpensive printing apparatus, and are rapidly becoming widespread.
The colorants for the inks used in the inkjet recording system can be broadly classified into those that use pigments and those that use dyes. Of these, inks that employ a pigment as the colorant tend to be gaining popularity, as they offer the superior levels of light resistance, weather resistance and water resistance required for high-definition printing.
In terms of the solvent used, inks can be broadly classified as either aqueous inks or non-aqueous inks. In an aqueous ink, a water-soluble organic solvent and water act as the ink medium, and dispersing the pigment finely within this medium and then ensuring favorable stability of the resulting dispersion is problematic.
For this reason, an aqueous ink with improved dispersion stability has been proposed in which the pigment is encapsulated within a resin prior to dispersion within the aqueous medium (see Japanese Patent Laid-Open No. 2003-313389).